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Understanding Amblyopia

Good vision takes a team effort from the eye muscles, eyes, and brain. When the eyes don't work together or one or both eyes have trouble focusing, the brain has trouble understanding what's being seen. This can cause vision problems.

How the eyes work together

Each eye sees from a slightly different angle. This means that 2 different pictures are sent to the brain. The brain blends these pictures into one 3D image.

View of eyes and brain from top of head showing how images from both eyes are processed in brain normally.

When there's a problem

When the eyes don't work together, the brain receives pictures it can't blend together. The brain ignores (suppresses) signals it can't use. In most cases, signals from one eye are ignored. The signals from the other eye are interpreted as a flat image instead of a 3D image. During suppression, normal vision can't develop in the eye that's being ignored. This is called amblyopia.

View of eyes and brain from top of head showing blurry vision in one eye because of amblyopia. Image from blurry eye not processed in brain.

Other common eye problems

Alignment problems (strabismus). One eye looks in a different direction from what it's trying to see. This may happen all the time. Or it may happen some of the time.

Focusing problems. One or both eyes have trouble focusing. The brain receives blurry pictures. Focusing problems include:

  • Being nearsighted (distant objects look blurry)

  • Being farsighted (nearby objects look blurry)

  • Having astigmatism (both nearby and distant objects look blurry). In some cases, focusing problems are worse in one eye than in the other.

Other problems. In rare cases, sight in one or both eyes can be blocked. This can be caused by a problem such as a cloudy lens (cataract). An eye care provider can tell you more about this.

Online Medical Reviewer: Chris Haupert MD
Online Medical Reviewer: L Renee Watson MSN RN
Online Medical Reviewer: Marianne Fraser MSN RN
Date Last Reviewed: 12/1/2021
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